A separate double-winding 12-phase brushless DC motor drive fed from individual H-bridge inverters

This paper deals with a separate double-winding 12-phase BLDC motor fed from individual H-bridge inverters. The system is fault tolerant in that continuous operation is possible under fault conditions. Every phase is electrically independent from each other and doubly wound to intensify the redundancy of the system. Furthermore, each phase is asymmetrically 15 degrees apart to have the same torque ripple reduction effect as 24-phase counterpart. Two partial windings in each phase are taken control of by one inverter module. One module consists of two single phase H-bridge inverters and can be detached from other modules to be repaired or replaced while it is out of operation. In terms of motor drive, sinusoidal wave currents are applied to the stators for minimizing torque ripples and the operating efficiency at low rotational speed of motor is improved by series connection of the partial windings. Simulations and experimental studies are conducted to evaluate the performance of the system based on a prototype motor.